1. Field of the Invention
This invention pertains to material handling methods and apparatus and more particularly to such methods and apparatus combined with heat treating and cooling of the objects handled.
2. Description of the Prior Art
Castings come in various complex shapes. It is not uncommon for castings to include portions which are somewhat delicate, such as projections or webbing portions and the like. Raw castings are not suitable when they come from the mold for final assembly or use without being treated in further operations. For examples, the flashings have to be knocked off, inadvertent voids have to be filled in by welding, the casting often has to be welded or otherwise joined to other parts, the surface has to be painted or otherwise coated or treated and the like.
Universal jigs and fixtures for every type of castings are not available in the prior art. Moreover, special jigs and fixtures suitable for holding complex and irregularly shaped castings while these subsequent type operations are performed without injury to the coatings are expensive and complex. In addition, it is not uncommon to have to manipulate a casting in more than one position for more than one subsequent operation where orientation of the object in more than one selected alignment position is required. For example, it may be required to perform a welding operation on first one side and then the other where in both welding operations it is desirable to weld directly down on the part.
Some operations to castings also require masking of the untreated part from the treated part, such as when painting is done to one part while the rest is to be left unpainted or painted a different color.
Finally, it is often desirable to heat treat the casting prior to performing the next step. For example, when filling an inadvertent casting void, it is desirable to preheat the overall casting to a higher temperature level than room temperature before treating the specific spot to be welded. This is particularly true for alloy castings. The method in common use today in fabrication shops is to preheat such castings to 200.degree. F.-300.degree. F. or more in an air furnace or by merely subjecting such castings to torching. Needless to say, such preheating is extremely inefficient. It has been estimated that less than 1% of the BTU energy expended actually goes into the castings in the typical situation where castings are laid out on the floor around an open gas-jet flame. In addition, the heating is terribly non-uniform. Finally, the heat retention is poor, even when a blanket is put over such heated castings.
Therefore, it is a feature of the present invention to provide an improved method using improved, but simple, apparatus for holding even the most delicate of castings in almost any given position without injury to the casting.
It is another feature of the present invention to provide an improved method using improved, but simple, apparatus for uniformly and efficiently heating castings, storing the heat in the castings, and subsequently manipulating and holding the casting in a number of different desired positions for subsequent operations.
It is still another feature of the present invention to provide an improved method using improved, but simple, apparatus for manipulating, holding and masking objects for subsequent operations on the unmasked portions.